Tapping machine



F. M. SANDERSON TAPPING MACHINE Feb. 9 1926. 1,572,685

l Filed Nov. 30, 1921 2 SheetsSheet 1 lllllllllllllllllllllllll ,IINFran/f Sanderse/7,-

Feb. 9 1926.

1,572,685 F. M. SANDERSON TAPPING MACHINE 2 Sheets-Sheet 2 Filed Nav.30, 1921 I' Fran/M1 sonde ron,

e Patented Feb. 9,-1926.

^ FRANK E. SANDEBSON, F SWAMPSCOTT, MASSACHUSETTS,

UNITED STATES l 1,572,685 PMI-:NT OFFICE,

ABSIGNOB TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.. i

Tarrina MAGHINE.

v iippucation'nlea November so, 1921. serial No. 518,939.

lTo all whom z't may concern.'

Be it know that I, FRANK M. a citizen of the United States, Swampscott,in the county of ssex, State of Massachusetts, have invented certain newand useful Improvements in Tapping Machines, of which the following is aspecific'ation.'

This invention relates to tapping machines and has for its object theprovision of improved means whereby the tapping element is given itsaxial as well as its rotary movement in a simple, reliable and efficientmanner.

More particularly my invention relates to automatic machines for tappingnuts, although it obviously has various other applications. In automatictapping machines it is desirable to move the tap axially into engagementWith the work by a yieldable force thereby avoiding an overload on thetap dueto forcing it through the work faster than the pitch of thethreads will allow and also damage when an undrilled blank is fed to thetap, of my invention is to provide an improved .construction which willvmeet these conditions in a satisfactory manner. l

In carrying out my invention I employ helical gears, the end thrust ofwhich provide the axial movement of the tap with relation to the work.When the tap is rotated in the tapping direction it will be moved by theend thrust of the helical gears into engagement with the work and uponreversal of the direction of rotation it will be moved out of engagementwith the work by the end thrust of the helical gears.

SANnnnsoN, residing at In case the tap as it rotates is moved into'yengagement with a blank 0r undrilled iece of-work it will' be heldagainst the b ank or work by a force equal to the end thrust of thegears. Since the end thrust has a definite maximum value, the tap is ineffect yieldably held against the blank or undrilled piece of work,whereby damage to the tap is avoided.

For a consideration of what I believe to be novel and my invention,attention is directed to the accompanying description and the claimsappended thereto. y

Figure 1 is a side elevation of my invention, partly in section showingthe arrange- 'ment of the different elements; Figure 2 is and a furtherobject moved; Figure 3 is a view partly insection, along line 3--3 ofFig. 2 looking in the direction of the arrows; Figure 4 is an end viewof the driven shaft showing the friction retarding means and method ofsecuring lthe same; and Figure 5 is a perspective view showing some ofthe elements of my invention and their relation to each other. y

Referring to the drawing, 10 indicates a base or framework on which isjournaled a shaft 11 which carries a worm `12- and a pulley 13. Shaft 11may be driven by any suitable means. In the present instance it is shownas being driven by the pulleyv 13 which is belted to any suitable sourceof power. Meshing with the vworm 12 is a` worm gear 14 which issupportedl by the base 10 and has a projecting stud 15 u on which one'end of a link 16 is journa ed. The other end of link 16 is journaled toa movable stud 17 mounted in slot `18 of a segmental .gear 19. Theradial slot 18 makes it possible to adjust the travel of segmental gear19. The segmental gear 19 is mounted on a stub shaft 20 supported bybase 10 and meshes with a pinion 21 mounted on a shaft 22 which carriesa helical gear 23. Stub shaft 20 is supported by the base 10. Thehelical gear 23 meshes with a helical pinion 24 which is of greaterlength than the thickness of gear 23f and is cut or mounted'on a shaft25 journaled to the frame 10. Shaft 25 carries a chuck 26l and a tap 27on one end and a friction retarding means on the other. The frictionretarding means comprises a forked member 28 which is loosely mounted onshaft 25 and has a plurality of discs 29 composed of leather or likematerial disposed on each side of it and held lses inplace by discs 30which are'keyed to a shaft 25. The discs 30 are free to move axiall onthe shaft 25.' A nut 31 is screw threa ed on the end of shaft 25 for thepurpose of varying the friction means. -A rod 32 fastened to the base orframe work 10 prevents the forked member 28 from turning with shaft 25.

Associated with the above described elements is a hopper 33 which feedsthe articles to be threaded to the tap. The hopper 33 is mounted uponrods 34.- and secured thereto by any suitable means. As shown this meansconsists of a frame work composed of tubular members 34 and end pieces34b and 34. This framework can be set at any desirable point alonthe-rods 34, the' hopper 33'being fastened in an upright position onmember 34". A spring member 36 having a slot 45 is located below thehopper 33 and supported on a stud 37 projecting from the casing. Thespring member 36 is secured to the stud 37 by meansof a member 38 and aset screw 39. The upper end of spring member 36 is biased against a pin40 on a sliding rod 41 by a spring 42. A

roller 43 is mounted on the inner end of..

sliding rod 41 and rolls on a side of segmental gear 19 and a cam orraised surface 44 which is provided for actuating the hopper dischargedevice as it rolls under roller 43.

The operation is as follows: As shown in the drawing a nut is beingtapped. The tap is proceeding through the nut in a right hand direction(Figs. 3 andl 5). Assume that the segmental gear 19 (Fig. 1) has ben totravel in a counterclockwise direction and that the tap 27 is about toengage the nut to be tapped. As the segmental gear 19 continues incounterclockwise direction the helical gear 23 (Fig. 1) will rotate in aclockwise direction and cause the tap to rotate in a counterclockwise orrighthand tapping direction and at the same time cause the tap to bethrust toward the nut by reason of the thrust caused by the helicalgears. As the segmental gear 19 continues in the above direction theraised or ca m surface 44 (Fig. 1) onsegmental gear 19 `will approachthe roller 43 (Fig. 3) on the sliding rod 41 which operates the hopperdischarge mechanism. When the roller 43 comes in contact with thesurface 44 the slot 45 (Fig. 3) will be moved adjacent the last nuttapped and will allow it to drop from the machine. It will be noticedthat the nut being tapped as well as those in the hopper are supported bthe tap when the discharge of the iinishe nut takes place.

Assume now that the segmental gear 19 has reversed its direction oftravel. This will reverse the direction of rotation of the tap and alsothe direction of the aforementioned thrust due to the helical ears.

This will cause the tap to be rawn from the nut. At the same time thecam surface 44 will pass from under the roller 43 and allow thedischarge mechanism to close the hopper in time to catch the finishednut as it drops off the tap. This nut will provide a support for thenext nut to be tapped.

The friction device on the end of shaft 25 operates as follows: Thediscs 30 being fixed on the shaft 25 will rotate and cause the frictiondiscs 29 to also rotate. As the discs 29 rub against stationary forkedmember 28 a load will be created on shaft 25. This Will insure thelateral movement of the shaft 25 in response to the end thrust of thehelical gears when the tap is not in cony of rotation of driving meansis immaterial as my machine will Work equally well when driven in eitherdirection and further after having once started in a given directionthere is no need of any reversal in the driving means. I therefore amable to also dispense with the need of shifting belts, in the event of aline shaft drive and electrical connections in the event of a directmotor drive. And further in the event of a blank nut or undrilled workpiece .being fed to the tap no damage Will be done as might be the caseif the tap were driven axially by other means. The end thrust of thegears having a certain definite value will cause the tap to be ressedagainst the blank Work piece by a orce equal to the end thrust and att-he same time permit the tap to rotate. As soon as the tap hascompleted a tapping cycle the blank work piece will be discharged fromthe machine in the usual manner Without any need of stopping the machineto remove it. v

In accordance with the provisions of the patent statutes, I havedescribed the principle of operation of my invention, together withtheapparatus which I now consider to represent the best embodimentthereof', but I desire to have it understood that the apparatus shown isonly illustrative and that the invention can be carried out by othermeans.l

What I claim as new and desire to secure by Letters Patent of the UnitedStates, 1s:-

1. In a tapping machine, a thread lcutting tool, a shaft having axialand rotary movement supporting said tool, a helical driving gear for theshaft, means for imparting oscillatory movement to said driving gear,and a helical pinion on the shaft with which the gear meshes, saidpinion being of greater length than the thickness of the gear.

2. In a tapping machine, a thread cutting tool, a shaft having axial androtary movement supporting said tool, a helical driving gear for theshaft, means for imparting oscillatory movement to said driving ear, ahelical pinion on the shaft with whic the gear meshes, said pinion beingof greater length than the thickness of the ear, and means connectedwith the shaft or imparting thereto an adjustable braking load.

lthe driving gear, means connected with the shaft for imparting theretoa braking load, a ho per, a movable member below the hoper aving a slotwhich registers with the op erwhen the member is moved, a cam sur ace onthe driving gear, and follower means for the cam connected with themember for moving the latter to carry the slot intoregistration with thehopper.

4. In a tapping machine, a thread cutting tool, a rotating shaft havingvaxial movements supporting `said thread cutting tool, helical gearsdriving said shaft, and af friction means on said shaft, the end thrustof the helical gears beingy utilized to impart axial movement tosaidshaft.

5. In a tapping machine, a driving shaft having a uniform direction ofrotation, a tool supportin shaft, and means comprising a link an helicalgears for imparting a forward and reverse direction of rotation and aforward and reverse axial thrust to the tool su porting shaft.

6. In a macli) 1ne for tapping nuts, a` tool supporting shaft havingforward and reverse rotary and axial movements, a helical -gear drivingsaid tool supporting shaft,

means connected with said gear for im arting thereto an oscillatorymovement, a elica pinion carried by the shaft, said pinion being inmeshing engagement with the gear and being of greater length thanthethickness of the gear, the length of the pinion` being such -that saidmeshin engagement. is maintalned throughout t e length of the axialmovements of the shaft, the end thrust of said helical gear beingutilized to impart the axial movements to said shaft through theintermediaryv ofthe pinion, a work` holding member, a. hopper, and meansassociated with said hopper for automatically supplying work pieces tosaid work holding member.

7. Ina tap ing machine, a thread. cutting tool, a sli cutting tool, andhelical gears driving said shaft, one of said gears being in the form ofan elongated pimon carried by the shaft, i

said helical gears being arranged to give an inward thrust on the shaftdurin the tapping operation and an outward t rust on the shaft duringthe removal operation of the tool, and said shaft being axially movablein response to said inward and outward thrusts.

In witness whereof, I have hereunto set my hand this 28th day ofNovember, 1921'.

i FRANK SNDERSON.

aft supporting said threadv

